Was donated a bike, help!! rear brake caliper

Push them together, the strudle at the top left that the cable runs through, clips into the metal part attached to the left v brake.

Start from the other end of the silver brake cable (called the inner brake cable).

Make sure the pill-shaped piece of metal on the the end of the inner cable is hoked into place inside the brake lever mechanism.

Make sure the black outer cover is seated into the brake lever.

Follow the outer back towards the frame. I bet this wire has two black outer covers – one in the front and one near the back.

Both ends of both covers needs to be a seated into some kind of frame mounting lugs, or the brake doesn’t work and cannot be put together.

Properly:

Lever⊏======⊐———–⊏======⊐≈≈≈⋑—⊛Brake Fixing bolt.

In your picture there is way too much wire between the brake noodle(≈≈≈⋑) and the bolt, so I assume one or both the housings has slipped out of their lug:

In your picture (probably)

Lever⊏======⊐———-======⊐≈≈≈⋑——-⊛Brake Fixing bolt.

Get the housings back in their lugs, and then try to squeeze he brakes together and get the noodle hooked in.

if the housings ARE in the correct position, you need to adjust the cable length as others have talked about

Good luck with bike!